Sole à la Hollandaise

Sole à la Hollandaise (whole sole gently poached with potatoes and melted butter) teaches the hardest kind of restraint: when there is nowhere for careless heat to hide. The one true thing to know before touching a pan is this: the water may reach its first boil, but once the lid goes on it must only tremble. A hard boil tightens sole, tears its fine surface, and turns tenderness to cotton.

The original method assumes a fish kettle large enough to hold a whole sole and a hand free to move it from water to service napkin while the potatoes and butter arrive at precisely the same moment. There is no saucier, permanent stockpot, or salamander to replace, because the absence of a built sauce is deliberate. At home, two deep lidded skillets stand in for the fish kettle, and a clean unscented linen napkin on a warmed platter drinks the last poaching water. The fish kettle is brigade scaffolding and can go. The salted-water poach, the linen, the plain potatoes, the green parsley, and the melted butter are the dish, and they stay.

The source is built around one whole sole and 2 ounces of butter. For four servings, the fish becomes two 1¼-pound soles, each serving two, and the butter becomes 4 ounces. Nothing is enriched, perfumed, or hidden. Served correctly, the flesh is pearly and moist, the parsley startlingly green, and the potatoes ready to catch their share of butter. One cook, one stove, one evening. Keep the covered poach below a boil; everything else is punctual service.